Due to chlorination, CPVC resins have a higher upper temperature limit as compared to vinyl chloride-based resins (vinyl chloride resins, polyvinyl chloride; hereinafter, simply referred to as “PVC resin”). Accordingly, CPVC resins are used in various fields such as fields of heat-resistant pipes, heat-resistant industrial plates, heat-resistant films, and heat-resistant sheets.
In general, a CPVC resin is produced by chlorinating a PVC resin by supplying chlorine into an aqueous slurry that has been obtained by suspending PVC resin particles in an aqueous medium. Typically, in a case where chlorination is carried out by photochlorination, UV irradiation is carried out by use of a mercury lamp so as to produce chlorine radicals (Patent Literature 1).
Further, there is a report on a method of obtaining chlorinated polyolefin particulates in one reaction tank. According to this method, by the step of dissolving chlorine into an aqueous slurry containing polyolefin particulates under a condition where no radical is produced, chlorine is penetrated into the particulates. Then, the step of chlorinating the particulates is carried out by heating or/and light irradiation. By repeating these two steps of dissolving and chlorinating alternately, chlorinated polyolefin particulates are obtained (Patent Literature 2).
In the above production method, a chlorination reaction is carried out by putting a mercury lamp 102 that is protected by a glass tube 101 in an aqueous slurry 105 of a PVC resin, as illustrated in FIG. 7.